Governor-damper.



No. 677,064. Patented June 25, NM. H. COOKE.

GOVERNOR DAMPER.

(Application filed Sept. 27, 1900.) (No Model.)

' 2 sheets sheet l.

|NVENTOR,

ATTORNEY.

No. 677,064. Patented June 25, I90]. H. CHOKE.

GOVERNOR DAMPER.

(Applicatipn filed Sept. 27, 1900.)

2 Sheets-Sheet .2.

N NTOR I EQ/ ATTORNEY (No Model.)

xavfififii UNITED STATES PATENT OFFICE.

HARTE OOOKE, OF AUBURN, NEW YORK.

GOVERNOR-DAM PER.

SPECIFICATION forming part of Letters Patent No. 677,064, dated J une25, 1901.

Application filed September 27, 1900. Serial No. 31,291. (No model.)

, To all whom, it may concern:

Be it known that I, HARTE OOOKE', a citizen of the United States, and aresident of Auburn, in the county of Cayuga, in the State of New York,have invented new and useful Improvements in Governor Dampers, of whichthe following, taken in connection with the accompanying drawings, is afull, clear, and exact description.

This invention consists of an improvement in dash-pots or dampingdevices such as are ordinarily used to steady the action of centrifugalgovernors in order that in addition to their usual function they maywhen connected to steam-engines or other prime movers used for drivingalternating-current electric generators in parallel prevent trouble fromwhat is known as the surging or hunting of the generators.

My said invention causes the dash-pot to give a very heavy dampingeffect for the very short period of time which is necessaryin order toprevent the surging of generators from affecting the governing, but tooppose the tendency of the governor to respond to a change of speedpersistent beyond the said short-time period above mentioned by only thecomparatively slight damping efiect or drag found necessary to givestability to the governor in ordinary kinds of service, this change ofdamping eifect being automatically brought about by the pressure of thefluid in the dash-pot causing avalve, delayed for the said short periodby an auxiliary dash-pot, to

open an enlarged by-pass passage around the piston of the main dash-pot.

What is meant by the surging or hunting of generators may be describedas follows: When two generators of a kind are running in parallel, ifthey are out of phase with each other by even a very small amount thereis developed a powerful tendency to bring them into a similar phase,which tendency will increase the speed of the unit that is behind anddiminish the speed of the one that is ahead. WVhen the generators arebrought into similar phase in this Way, they will tend to overrun untilthe differen ce in their speeds is overcome by the above-mentionedtendency to come into similar phase, and the process will be repeated,each generator vibrating with respect to the other in the manner similarto a pendulum, but usually with a very short period of Vibration. Thisvibratory movementis called hunting or surging. When the engines orother prime movers driving these generators are provided withproperly-sensitive governors, they will ordinarily be acted upon by thechanges of speed just mentioned. The governor of the faster-moving unitwill tend to decrease its speed, and vice versa in the case of the otherunit. Since the governor requires some time to eifect such changes ofspeed, due to the inertia of its parts and other causes by reason ofthis lagging, the generator will have reached the end of its vibratorymovement, above mentioned, before the governor will have begun to act.Therefore taking the case of two units, for example, on the unit whichis running slower the governor will not have actually begun to increaseits speed on account of its slower running until it is on the returnstroke of this vibratory movement and is hence the faster-running unitof the two. In this way the efiect of the governor may actually increasethis vibratory movement or surging of parallel-runnin g generators untilit causes an electrical disturbance, which will prevent their properperformance. I found that in order to prevent this trouble fromoccurring it was necessary to increase the resistance 'of the dash-potsuch as is ordinarily used to give stability, as mentioned'above, byreducing the area of the by-pass around the dash-pot piston to such anextent that it affected very u-nfavorably the regulation of the speed ofthe prime mover by the governor, for by this greatly-increased dampingefiect the governor was made so sluggish that it could not respondquickly to changes of speed caused by sudden changes of load and thatthis lagging efi'ect was so great that before the governor had time torespond a considerable fluctuation in speed would have taken place. Inorder to avoid this, I have resorted to the novel construction of thedashpot' as hereinafter described, which is arranged so that theresistance of the dash-pot to a tendency of the governor to respond to achange of speed, persistent beyond the short time-period for which theheavy damping effect is necessary to prevent the governor being affectedby the surging, will cause an enlarged by-pass to be opened, allowingthe governor to be very sensitive to any change of speed persistentbeyond the said short timeperiod.

In the annexed drawings, Figure l is a side view of a centrifugalgovernor equipped with my improved dash-pot or damping device, Fig. 2 isa transverse section of the same, and

Fig. 3 is an enlarged longitudinal section of said dash-pot.

Similar letters of reference indicate corresponding parts.

0 represents the cylinder of the dash-pot.-

Said cylinder is pivoted to the governor in the position shown in Fig. 1of the drawings. The ends of said cylinder are provided withstuffing-boxes O O, the necessary glands of which-areomitted in Fig. 3of the drawings.

a denotes a piston arranged in the cylinder 0 and attached to a rod d,theends of which pass through the stuifing-boxes O O, as shown moreclearly in Fig. 3 of the drawings. One end of .the rod 61 is connectedto the centrifugalweight D or other suitable actuating part of-thegovernor.

The piston a is provided with asmall bypass orifice o, forminga limitedpassage for the oilor other fluid with which the-cylinder is charged.The said'orifice is smallenough to prevent a sudden movement of thecentrifugal-weight and give sufficient drag upon its movements toprevent the governor from bein-geffected by thesurging of the electricgenerator; but it will allowthe governorto adjust itself to very slightchanges of speed if of long duration, and when such. changes are not ofsufficient magnitude to open the by-pass valve hereinafterdescribed, theorificeotalsoserving as a safety device forrpreventing a dangerousincrease of speed in case theloy-pass valve accidentally fails tooperate.

In order that any tendency of the governor to respond to a change ofspeed may automatically substitute .a comparatively slight drag-ordamper effect for the heavy drag or damping effectof the said smallorifice 0 afterthe said short time period has elapsed necessary toprevent the governor from beingeaffected by the surging of the electricgenerator before described, I employ a releasing device which mayconsist of a valve ina large by-pass communicating with oppositeends ofthe cylinder 0 and controlled by anauxiliary dash-pot, as shown in Fig.3 of the drawings, in which Z) representsthe aforesaid by-pass,consisting of-a longitudinal channel in a tubularenlargernent B on theexterior of the cylinder 0. One end of said channel or by-passcommunicates directly with one end of the interior of said cylinder,while the opposite end of said by-pass terminates in a cylindricalchamber e, which is axially inline with a small radial passage 0,communicating with the interior of the cyl inderyO adjacent to the endthereof. The passage 0 extends only part way toward the channel orby-pass b and is of a smaller didirection to that indicated by thearrow.

ameter than the chamber 6 to forma shoulderfat their junction. Saidchamber constitutes the auxiliary dash-pot and serves as a seat for apiston-valve g, which is connected by a stem g to a piston h and is heldon the shoulderf by a spring 6', bearing on the outer face of the pistonh. The valve 9 and piston h are a sufficient distance apart to benormally disposed at opposite sides of the bypass, as shown in Fig. 3 ofthe drawings. The shoulder fis a suitable distance from the said by-passto allow the valve 9 a predetermined degree of travel in the chamber 6without opening communication between the by-pass b and passage 0. Thepiston his provided with a small port 7 for the purpose hereinafthat thevalveg may yield to,a-slight pressure of the fluid in theradial passage0.

The operation of the described by-pass and auxiliary dash-pot is asfollows: The piston Ct gives the heavy drag upon anyanovement 0f thecentrifugal weight D, causedby the smallness of the orifice 0, until thepressure applied to the piston a by the governor in the direction ofthearrow has continued fora sufficient period of time by reason of thepressure ofthe fluid on the valve (,connected to the piston 7;, due to.said pressure .on the fluid by thepiston aand the resistance of smallorifice 0 toescape of the fluid ,to force enough fluid fromthe chamberethroug-h port t' of the piston h to thespace between :said piston handthe by-pass valve g toallow said valve to move to a position which openscommunication between the .two ends ofthe. cylinder through the large bypass 1), thus greatly reducing the resistance to the :mo-

.tion of the piston CL and correspondingly vreducing the damping effectof the .dash -pot on the governor.

A second by-pass valve and-auxiliarydashpot is provided, as indicated by.dotted lines atP in Fig. 3 of. the drawings,-and is arranged tooperatein a similar mannerwh'en the force tendingto move the piston a isman opposite By a properproportioning.of the sizeofthe port 1'- withreference to the-size of the piston h of auxiliary dashpot thetimeintervalbefore the opening of the bypass (during which interval theheavy damping effect .will bein force) can be determinedand canbegmadeofIIO sufficient length to preventthegovernorfrom beingafiected by thesurging of the electric generator and at the same time the interval maybe .made briefenough to enablethe governor to "fulfilsuccessfully, itsfunction -as-a regulator of the speed of the prime vmover.

I- do not limit myself to the specific con struction and combination ofthe component parts of my invention, inasmuchas theyare susceptible ofmodifications withoutdeparting from thespirit ofmy invention.

WVhat I claim asmyinvention is- 1. The combination with a prime mover, a

governor consisting of a centrifugal weight whose force is opposed by aspring or gravity mounted on a suitable frame; and a main damper, themoving part of which is connected to said centrifugal weight, saiddarnper having a releasing device so placed as to be automaticallyoperated by the resistance of the said main damper, of an auxiliarydamper connected to a moving part of said releasing device as set forth.

2. The combination with a prime mover, a centrifugal governor comprisingcentrifugal weights controlling the prime mover, a dashpot comprising acylinder carried on said governor, the piston-rod connected to anactuating part of the governor, asmall by-pass communicating with theinterior of the cylinder in front and rear of the piston, and largeby-passes communicating with opposite ends of the interior of thecylinder, of auxiliary dash-pots controlling said large bypasses as setforth.

3. The combination with a shaft rotating in unison with a prime mover, agovernor-frame, centrifugal governor-weights opposed by springs, and acut-off eccentric, the position of which is controlled by the saidcentrifugal weights, of a main dash-pot cylinder mounted on saidgovernor, a piston in said cylinder provided with a small by-passorifice through it, and having its rod connected to an actuating part ofthe governor, large by-passes communicating with opposite ends of theinterior of the cylinder, and auxiliary (lashpots controlling said largeby-passes as set forth.

4. The combination with a shaft rotating in unison with a prime mover, agovernor-frame, centrifugal governor -weights opposed by springs, and acut-off eccentric, the position of which is controlled by the saidcentrifugal Weights, of a main dash-pot cylinder mounted on saidgovernor, a piston in said cylinder provided with a small by-passorifice through it, and having its rod connected to an actuating part ofthe governor, large by-passes communicating with opposite ends of theinterior of the cylinder, a chamber extending from each of said largepasses and in range therewith, a valve in each of said passes, a pistonin the chamber connected to said valve and provided with a port, and aspring in the aforesaid chamber pressing upon the piston of the chamberand thereby holding the valve yieldingly to the stopshoulder as setforth and shown.

In testimony whereof I have hereunto set my hand and afiixed my sealbefore two subscribing witnesses.

I'IARTE COOKE. [L. 8.]

lVitnesses:

J. J. LAASS, H. B. SMITH.

